The question came up this spring when the state considered severing its oversight of many young adults who have been in its care since they were removed from their parents’ homes for safety and other issues.

In the end, the state decided to continue its services to 18- to 21-year-olds, but with fewer funds. And in many families, older children as staying home longer.

That fits in with a view of adulthood sometimes used by sociologists, who define it as the point at which someone has the ability to support themselves.

Helen Mederer, chair of the department of sociology and anthropology at the University of Rhode Island, says the dividing line moves with the structure of the economy.

In a farming society, self-sufficiency might have come in the mid-20s, at least for the oldest son, who stood to inherit the farm when the father died. But age dropped in the industrial era, when a young factory worker could earn a family income.

The point of self-sufficiency may be going up again, because in the information age much more education and skill are needed to pay rent, student loans, and three meals a day. Some students are staying in college longer, getting more advanced degrees, and remaining dependent on parents, sometimes living with mothers and fathers.

One adult pursuit keeps getting put off: marriage.

The age of “first marriage” has gone up in a half-century. In 1955, the median age was 20 for women and 22 for men, according to the Census Bureau. By 2005, it was 25 for first-brides and 27 for first-grooms.

Asked whether her own students are “more adult” in the 25 years she’s been teaching, Mederer says, “I would say in some ways less adult and some ways more. More have to pay for education, and I see them juggle work and school much more than before.”

But she says parents seem increasingly involved in students’ lives.

There’s an academic term for this: “Helicopter Parents” — who “hover” over their children and query college deans and faculty about students’ academic progress.